Tennessee’s unemployment rate for August increased to 8.5 percent, up from the July revised rate of 8.4 percent. The national unemployment rate for August 2012 was 8.1 percent, 0.2 percentage point lower than the July rate.

The state unemployment rate is seasonally adjusted while the county unemployment rates are not. Seasonal adjustment is a statistical technique that eliminates the influences of weather, holidays, the opening and closing of schools, and other recurring seasonal events from economic time series.

Knox County had the state’s lowest major metropolitan rate of 6.7 percent, unchanged from the July rate. Davidson County was 7.4 percent, unchanged from the previous month. Hamilton County was 7.7 percent, down from 8.4 percent, and Shelby County was 9.0 percent, down from 9.7 percent in July.